When it comes to signing outside free agents, the Steelers usually look for role players who come at a reasonable price. In the 20 years since NFL free agency began, they've rarely signed free agents who have made a big impact.

The Steelers have signed free agents who have had the wrong kind of impact, however.

Let's take a look at the 10 biggest free-agency busts in Steelers history and hope the Steelers don't sign anyone in the coming weeks who would affect this list.

10. Cedrick Wilson, WR

Cedrick Wilson is the most infamous player on this list because of his off-the-field problems, but he's at No. 10 because he stuck around longer than anyone else on the list.

Wilson came from the San Francisco 49ers and caught 81 passes for the Steelers between 2005 and 2007

He never quite matched his production in San Francisco, however, and the Steelers didn't like him enough to keep him around after he was charged with simple assault for hitting his girlfriend in March 2008.

Wilson posted career highs with 47 receptions and three touchdowns with the 49ers in 2004. The Steelers signed Wilson after the 2004 season when it became apparent they wouldn't be able to re-sign Plaxico Burress.

Wilson never caught more than 37 passes in a season for the Steelers and scored just two touchdowns in his three years in Pittsburgh. He never played in the NFL again after the Steelers released him.

9. Duce Staley, RB

The fact that Staley is even on this list says something about the Steelers' record in free agency. He wasn't a complete bust. He opened the 2004 season as the starting running back and ran for more than 100 yards four times to help the Steelers start the season, 6-1.

Staley had knee surgery during the offseason and didn't get a carry until Week 8 in 2005. In that game at Green Bay, Staley replaced an injured Jerome Bettis, who was the complementary back to starter Willie Parker.

The Steelers also were without Ben Roethlisberger in that game, but Staley ran for 76 yards on 15 carries with a touchdown in the Steelers' 20-10 win.

Staley ran for 64 yards on 17 carries the following week in a win over the Cleveland Browns. After that game, however, Staley carried the ball just six more times as a Steeler.

8. Leonard Pope, TE

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Now we get to the real duds on this list, players who gave the Steelers little or nothing during their time in Pittsburgh.

Leonard Pope followed Steelers offensive coordinator Todd Haley from Kansas City in 2012, signing a one-year contract. Considering the uncertainty of Heath Miller's knee, it says something if the Steelers don't bring back Pope, who will be 30 next season.

It's not like Pope was expected to be a major part of the Steelers' offense, but three catches?

That's all Pope had in 2012 after catching 24 passes with Kansas City in 2011, his third season with at least 20 receptions.

Two of Pope's three receptions for the Steelers were touchdowns, but one of those TDs came in the meaningless season finale against the Cleveland Browns.

Another factor that pushes Pope to No. 8 on this list is the fact that he was passed over on the depth chart by David Paulson, a rookie drafted in the seventh round.

7. Travis Davis, FS

Being forgettable is one way to get on this list, and Davis played during one of the more forgettable years in modern Steelers history.

The Steelers signed Davis in 1999 after losing safeties Carnell Lake and Darren Perry in free agency.

Davis was part of a 6-10 team that year, in the midst of the Steelers' three-year playoff drought that lasted from 1998 to 2000.

Davis came to the Steelers after four years in Jacksonville. He did intercept a pass and return a fumble 102 yards for a touchdown, but that was about it.

Even though he was just 27 at the time, Davis was done in the NFL after the Steelers released him.

Perhaps, the best thing about Davis is he indirectly led the Steelers to draft Troy Polamalu. The Steelers released him after the 1999 season and signed Brent Alexander to take his place. Alexander ultimately was replaced by Polamalu.

6. Kent Graham, QB

Steelers fans shouldn't forget how lucky they are that their team has Ben Roethlisberger.

One of the reasons the Steelers didn't make the playoffs between 1998 and 2000 is because their quarterback situation was unsettled.

Kordell Stewart lost the starting job late in the 1999 season, and the Steelers signed Kent Graham, who won the starting job to open the 2000 season.

Graham, who previously played for the Giants and Cardinals and had never started more than nine games in a season, went 2-3 in five games as a starter in Pittsburgh. He completed just 44.6 percent of his passes and earned a passer rating of 63.4.

Stewart started the last nine games of the season after Graham was injured and nearly led the Steelers to the playoffs. They finished 9-7.

Stewart did lead the Steelers to the playoffs the following season after the Steelers cut Graham. He earned a Pro Bowl berth as the Steelers reached the AFC Championship Game.

Graham appeared in three games for the Redskins in 2001, then he was finished.

5. Quincy Morgan, WR

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Unlike Kent Graham, Quincy Morgan actually accomplished something in the NFL before he came to the Steelers. That made him more of a disappointment in Pittsburgh, and therefore, a bigger free-agent bust.

Morgan caught 56 passes for the Cleveland Browns in 2002, leading the NFL with 17.2 yards per reception. He caught 38 more passes in 2003.

Morgan played in all 16 regular-season games for the eventual Super Bowl champions, but caught just nine passes. He returned kicks and was eighth in the NFL with 25.3 yards per kick return. But he never played another down for the Steelers after hurting his ankle in the wild-card playoff game at Cincinnati.

Morgan was one of the last players the Steelers cut before the 2006 season.

Perhaps, this had something to do with kicking at Heinz Field, but Peterson is the only player on this list who revived his career after he left the Steelers. He kicked for the 49ers in 2003 and 2004 and the Falcons in 2005, making 53 of his 62 field-goal attempts in those three years.

The Steelers lost eventual Hall of Fame cornerback Rod Woodson to free agency after the 1996 season, then signed Woolford from the Chicago Bears.

Woolford had 101 tackles and made the Pro Bowl in 1993. He had 32 interceptions in eight seasons with the Bears, including six in 1996.

It turned out the Bears let Woolford go at just the right time. He had four interceptions with the Steelers in 1997, but he was no Woodson. By the end of the season, Carnell Lake had to move from safety to cornerback when Woolford was demoted.

Woolford was released before the 1998 season, and at 32, his career was finished.

2. Jay Riemersma, TE

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Jay Riemersma is ranked second on this list because of the forgettable factor and because he was the poster boy for the Steelers' ill-fated attempt to become a pass-first offense behind Tommy Maddox in 2003.

In 2001, Riemersma was fifth in the NFL among tight ends with 53 receptions. He was the perfect guy to bring in for a team trying to get more offense from its tight ends.

But Riemersma caught just 17 passes in two seasons after the Steelers signed him from the Buffalo Bills. He's a bigger free-agent bust than Woolford because at least the Steelers reached the 1997 AFC Championship Game with Woolford on the team.

With Riemersma catching just 10 passes, the Steelers slumped to 6-10 in 2003.

The 31-year-old Riemersma caught seven passes in two starts in 2004, and his season ended after 12 games when he injured his Achilles.

Riemersma's flop turned out to be a blessing in disguise. The Steelers released him in February 2005. Two months later, they drafted Heath Miller in the first round.

1. Sean Mahan, C

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Sean Mahan is the Steelers' biggest all-time, free-agent bust because of the historical implication of his performance.

Beginning with Ray Mansfield in 1964, only four players regularly started at center for the Steelers for 42 years. The last three, Mike Webster, Dermontti Dawson and Jeff Hartings, all made multiple Pro Bowls.

Part of the reason the Steelers acquired Mahan was because new coach Mike Tomlin was familiar with him. He was on the Buccaneers' staff.

The problem was that Mahan could not uphold the Steelers' rich tradition at center. The Pittsburgh Post-Gazette said "he was overpowered by some of the bigger nose tackles in the league."

Mahan's ineffectiveness reached a whole new level in the playoffs when he committed a penalty that ultimately might have cost the Steelers the game.

In an AFC Wild Card Game at Heinz Field, the Steelers had narrowed a 28-10 Jacksonville Jaguars lead to 28-23 with about 10 minutes left in the game.

Ben Roethlisberger completed the two-point conversion pass to Hines Ward, which would have pulled the Steelers to within a field goal. But it was negated by Mahan's holding penalty. The Steelers attempted another two-point conversion after moving 10 yards back, and it failed.

The Steelers had to go for two when they scored another touchdown to go up 29-28. That attempt also failed, which allowed the Jaguars to win the game with a field goal.

The Steelers sent Mahan back where he came from, trading him to Tampa Bay before the 2008 season. He played two more seasons, starting four games in 2009.

Dishonorable Mention

Hartwig wasn't much better than Sean Mahan when it came to carrying the torch of the Steelers' tradition at center. He was released before the 2010 season after rookie Maurkice Pouncey beat him out for the starting job. At least he stuck around for two years, one year longer than Mahan, and he was part of a Super Bowl champion.

Todd Fordham, OT

The Steelers signed Fordham from Jacksonville in 2003 to compete for the starting job at right tackle. He started six games, then the Steelers traded him to Carolina before the 2004 season. Fordham never was a full-time starter in his career. So it's not like he was a huge disappointment.

Rich Tylski, OT

The Steelers signed Tylski after he played four years in Jacksonville. He started every game at right tackle for the Steelers in 2000, but was hampered by injuries in 2001. The Steelers released him after they drafted Kendall Simmons in the first round of the 2002 draft.

Jonathan Scott, OT

The Steelers signed Scott from the Buffalo Bills in 2010. When Max Starks was injured after seven games in 2010, Scott stepped in and started at left tackle for the rest of the season. The Steelers reached the Super Bowl with Scott protecting Ben Roethlisberger's blind side.

Starks was released before the 2011 season. Scott started at left tackle to open the season, but the Steelers called Starks off his couch after Roethlisberger was sacked 14 times in the first four games. Scott was released before the 2012 season.